Originally Posted by RustyCage
I agree with all of that, but it's just the full requirements of the League's goal included that Gotham had to reach a point of saturation in how corrupt it was for them to burn it down. For all the League knows, in TDKR, this point was avoided and amended despite Ra's failing.
I don't think the point was ever avoided. Ra's says it's "When a society reaches the pinnacle of its decadence". For the League that point came decades prior to Batman Begins, when they attacked Gotham financially. If the League believed broken societies were capable of fixing themselves in a permanent way, why would the League have any reason to exist? And that's the interesting thing. I think this very notion that Gotham can cure itself is utter blasphemy to them. It's an existence-threatening paradox that they cannot begin to consider. They may not have known about the Dent coverup, but their devout dedication to staying the course is vindicated when the truth finds its way to them. And that's what is so fascinating and scary about that to me. What happens when evil extremists have the truth on their side? What does that mean? What kind of power does that give them? Does it make them right? Or is a broken clock right twice a day?
So basically, the League are complete and utter dogmatists. I like to think of it as what would Ra's al Ghul do if he had survived (or if there was a Lazarus Pit in this universe)? He had already made it clear that he thought Bruce's crusade to fix Gotham was pointless because Gotham was beyond saving, just like he thought Thomas Wayne's efforts to fix Gotham were pointless. Even without the knowledge that the Dent Act was based on a lie, you can see how the League would still find this to be a temporary and insufficient solution to a more deeply engrained problem. It doesn't matter that Gotham has shown improvement, the "new" Gotham still does not fit into their vision for a new world, though its destruction lies at the center of it. It's the most prominent city in the world and it's decades past its expiration date.
Bane and Talia had very different methods than Ra's, but I do think they were carrying out his will in the sense that if he were alive, I think he'd very much be regrouping to attack Gotham again no matter the circumstances. In part because he was a vengeful man (a trait his daughter inherited), but also because his belief that Gotham couldn't be saved and had to be destroyed was unflinching and absolute.